Consistent with this notion, the present study demonstrated that the influence of ΔPNI on disease-free survival may be similar across all breast cancer subtypes, particularly in patients with ER-positive or HER2-negative breast cancer; however, this should be interpreted cautiously as there was no statistical significance in the number of patients with different subtypes owing to the small number of patients enrolled in this study. The gene discussed is ESR1; the disease is breast carcinoma.